The present invention relates to a yarn winding bobbin having a yarn catching slot of novel construction.
German patent application DE 39 23 305 Al discloses a yarn winding bobbin for the takeup of a yarn, in particular a synthetic filament yarn, and wherein the yarn is caught by a process involving codirectional movement of the yarn and a yarn catching slot. The yarn catching slot of this prior winding tube consists of an inlet portion and a clamping portion. The inlet portion is sufficiently wide so that the yarn drops easily down to the bottom thereof, but the clamping portion is relatively narrow and serves to grip the yarn and exert considerable tensile forces on the yarn.
In the known winding tube, a yarn trap is provided in the region of the inlet portion of the slot, which does not hinder the radial entry of the yarn into the inlet portion, but blocks, preferably in a form-locking manner, its radial- exit from the clamping portion.
It is the object of the present invention to provide a yarn winding bobbin having an improved yarn catching slot of the type having a yarn trap. The invention is particularly suitable for the processing of coarse yarns, or yarns having a high tensile strength, and wherein very high and very suddenly occurring yarn forces act upon the yarn trap. When the winding tube is formed of cardboard or wound layers of paper, there is a risk that in such cases the yarn trap, which also consists of layers of paper, is shredded. It is a further object of the present invention to avoid such shredding of the yarn trap.